Study On Some Aeroelastic And Stability Analyses Of Tiltrotor

Tiltrotor is a new type of aircraft. It has the advantages of both conventional helicopter and fixed-wing aircraft, and has a bright future. Tiltrotor's coupling of its wing, pylon and rotor is more complicated than helicopter's coupling, and the aeroelastic analysis and stability of tiltrotor appears very important.There wre two part of this paper. In the first part, the airplane mode's model of tiltrotor with rigid blades, rigid pylon and elastic wing was founded. The fundamental frequency and damping characteristics of this model were studied, and the result was well equal to reference. By this model, the influence to whirl flutter of some important system parameters, such as frequency blade and wing, were studied. Responses of tiltrotor to initial conditons in airplane mode were computed at typical flying speed. Nonliear analysis model of tiltrotor in helicopter mode was founded, and responses of the system to initial conditions were computed, and the stable slove was got.In the second part, the models of elastic blade and wing were founded with beam by finite element method. Nature characteristic (nature frequency and nature mode) of elastic blade and wing was studied, and the result was well equal to UMARC's. The uniform nonlinear analysis models of helicopter mode and flight mode of tiltrotor with elastic blades were founded by finite element method, and dynamic inflow was combined to model unsteady aerodynamics of rotor in helicopter mode to model the unsteady aerodynamic. By the uniform analysis models, nonlinear responses of tiltrotor to initial conditons in helicopter mode and in airplane mode were computed, and stability of system was checked.Compared to the research of tiltrotor in aeroelastic analysis internationally, the research in this field is to be lucubrated, so the productions of this paper can provide some referrence to research and design of tiltrotor domestically.